Table 2 Performance metrics from 10-fold cross validation for random forest classification of high and low function women on each of 11 feature sets

From: Accelerometer-based predictive models of fall risk in older women: a pilot study

Set

Accuracy

Precision

Sensitivity

F1-Score

AUC

Feature groups

Top-five features

1

69.0%

75.0%

0.873

0.807

0.545

Gait

STD_STEP_TIME, STD_STRIDE_TIME, MEAN_STRIDE_TIME, MEAN_STEP_TIME, CADENCE

2

71.9%

79.0%

0.845

0.817

0.665

X-axis

X_MEAN, X_COV, X_SMA, X_PFREQ, X_ENERGY

3

72.7%

79.1%

0.858

0.823

0.661

X-axis, gait

X_MEAN, X_COV, X_SMA, X_RMS, X_ENERGY

4

75.9%

82.6%

0.855

0.840

0.730

Y-axis

Y_PFREQ, Y_MCR, Y_COV, Y_STD, Y_MAD

5

76.2%

82.5%

0.862

0.843

0.727

Y-axis, gait

Y_PFREQ, Y_MCR, Y_RMS, Y_STD, Y_COV

6

70.9%

83.3%

0.760

0.795

0.759

Z-axis

Z_COV, Z_MEAN, Z_MAD, Z_STD, Z_PFREQ

7

73.1%

84.1%

0.785

0.812

0.771

Z-axis, gait

Z_COV, Z_MEAN, Z_MAD, Z_STD, Z_SMA

8

70.9%

79.3%

0.822

0.807

0.616

Vector magnitude

MAG_PFREQ, MAG_MAD, MAG_MCR, MAG_P2P, MAG_SMA

9

71.4%

78.5%

0.846

0.814

0.616

Vector magnitude, gait

MAG_PFREQ, MAG_MCR, MAG_MAD, MAG_MEAN, MAG_SMA

10

79.3%

84.6%

0.881

0.863

0.834

XYZ, cross-correlations

Z_COV, XZ_CORR, Z_MEAN, X_MEAN, Z_MAD

11

78.9%

84.4%

0.877

0.860

0.846

XYZ, cross-correlations, gait

Z_COV, XZ_CORR, Z_MEAN, X_MEAN, Z_MAD

AVG

73.7%

81.1%

0.842

0.826

0.706

  
  1. Note: With a two group classifier, there are 4 possible results: true positive (TP), true negative (TN), false positive (FP), and false negative (FP). Accuracy = (TP+TN)/(TP + TN + FP + FN). Precision (also referred to as positive predictive value) = TP/(TP + FP). Sensitivity (also referred to as recall) = TP/(TP + FN); F1 score = 2TP/(2TP + FP + FN); AUC = area under curve in ROC analysis
  2. Top-five features in each feature set are listed. Full list of features included in each feature group can be found in supplementary data
  3. MAG vector magnitude, SMA signal magnitude area, COV coefficient of variance, CORR correlation coefficient between two axes, PFREQ peak frequency, MAD mean amplitude deviation, MCR mean crossing rate, STD standard deviation, P2P peak-to-peak amplitude, RMS root mean squared. Prefixes indicate axis or vector magnitude—X anteroposterior, Y: vertical, Z: mediolateral